Solutions to produce spatial images with laser technology, such as holograms, stereograms, etc. are known. It is a shortcoming of the known laser systems that they are inadequate for producing three-dimensional images from video signals. A method and apparatus for producing three-dimensional pictures is known from the International Patent Application published under WO 94/23541. This specification discloses two basic methods for producing three-dimensional images.
According to a first version of this known solution, the modulated laser beams are subjected to deflection according to the directions defining a field of view, and controlled in time, so that the modulated laser beam impinges on a predetermined pixel deflected, with a given entry angle, or parallel displaced, and exits from the pixel deflected or without further deflection, according to a predetermined direction defining the field of view. A disadvantage of this solution is that the laser beam needs very precise focusing and positioning, because the direction of the exiting laser beam is determined by the entry point within the pixel.
According to the other version, the modulated laser beam arrives at the pixel without any deflection within the entry points, and the time-resolved deflection, dependent of view directions is effected with controllable active optical elements, placed in each pixel. The angle deflection, dependent of the intensity, is performed by the active optical element. An advantage of this solution is that less precise focusing and positioning is needed, but a further disadvantage is that the active optical elements make the apparatus very expensive.
Hence it is an object of the invention to provide a method and apparatus for producing three-dimensional images, enabling to produce three-dimensional images using video signals containing three-dimensional image information, and this without the need for using expensive focusing and positioning elements. It is a further object of the invention to provide a method and apparatus for producing three-dimensional images, where a high-resolution screen does not contain expensive active beam deflecting elements, and which may be manufactured economically.